This relates to a monitor system for an electric cable shovel, and a method of operating a monitor system for an electric cable shovel. Electric cable shovels are large excavating machines that find wide use in material removal operations, such as for example in mining. The process of removing material from a mine worksite commonly aided by the use of a digital model of the topography of the worksite, including information defining locations of ore deposits within the worksite, as well as the different concentrations or grades of ore and the topology of the worksite. The site model may include property boundaries, not only of the mine itself, but also any internal boundaries which mark portions of the mine that may be separately owned. Using this information, a mine plan can be developed which defines the way in which the top soil and ore are removed from the worksite. In the past, it has been common for surveying and stake setting crews to mark the worksite with flags or stakes to reflect the site model. The site model and the location of the stakes must then be updated periodically to reflect the mining progress at the site.
To reduce the amount of labor required to set stakes and to simplify the operation of an electric cable shovel, several systems have been developed which keep track of the excavation process. One such system is disclosed in U.S. Pat. No. 5,864,060, issued Jan. 26, 1999, to Henderson et al. The Henderson system monitors the progress of an excavator at a worksite based primarily on the time that the machine is maintained in various positions. The system determines the angular velocity of the excavator as it rotates about a vertical axis from a position where digging is accomplished to a position in which the excavator is unloaded. The machine is stopped in response to the angular velocity being less than a specified amount, and this condition is detected. The length of time that the machine is stopped is measured. The work cycle of the machine is then determined, based on this measurement.
Another monitor system is shown in U.S. Pat. No. 5,850,341, issued Dec. 15, 1998 to Fournier et al. In the Fournier system, the operation shifting the transmission of an excavator between forward and reverse is detected. This is taken by the system as an indication of digging with the excavator. The Fournier system and other systems are not as direct and straightforward as might otherwise be desired. Further, it is desirable that the monitor system be able to determine the nature of the ore being mined and distinguish soil from the soil having a large ore content which may have little or no ore content.